Already it seems like an impossible stretch of memory but it is true and it is why the closing rites were filled with so much pride and emotion and, maybe above all, a feeling not so much of a job well done but a spirit regained, a sense of ourselves and the world around us that might just defy, for a little while at least, the bleakest forecasts.
These, it was possible to believe as the flame was put out not as some vulnerable candle in the wind but a strong symbol of reasserted values, were the Olympics that celebrated more vividly than any in living memory the enduring gusto of an embattled world.
These were the Games you couldn't fail to love. The Games that seduced cold-headed calculation of cost and reward with their sheer vitality. The Games that took on astonishing life.
They were the Olympics of Usain Bolt, a fabulously exuberant expression of superb natural gifts. Of Mo Farah, who reset the heartbeat of the nation, and Jessica Ennis, whose arrival in this stadium first suggested that something extraordinary, unforgettable, was in the air.
They were the Olympics which, hour by hour, day by day, set a standard of performance that was maybe most perfectly achieved by the Masai tribesman David Rudisha who broke the 800m world record so beautifully, so inevitably, his stride has to be stored away in the memory of anyone who saw it.
They were also, most significantly, the Olympics attended by people who cared, passionately, about the meaning of what they were seeing. They clamoured and scavenged for tickets, were enraged by the sight of empty seats in the first few days; they cheered and they cried and they found in their unbridled enthusiasm at least a passing fascination for previously obscure disciplines like handball and taekwondo.
As they did so they gave fresh substance to the flattering remark of International Olympic Committee president Jacques Rogge that the Games had come to a place which in so many ways was the founder and organiser of modern sport.
At the time it seemed not much more than a nicety to make his hosts feel a little better about the way they viewed themselves. Soon, though, there were so many reminders that he had merely uttered historic fact, which so many times these past two weeks unfolded again like some giant sunflower.
It reached out into every corner of the Olympics. It touched the swimming pool where the American Michael Phelps fought the years gracefully enough to become the most successful Olympian of all time. It was there at the rowing lake of Eton College, where Heather Stanning, a captain of the Royal Artillery soon bound for duty in Afghanistan, and Helen Glover delivered Britain's first gold with the effect of kicking that first stone which starts the avalanche.
It crowded so deeply along the road on which Bradley Wiggins, the laconic conqueror of the Tour de France, added another Olympic gold medal to his collection before sitting on a mock throne at Hampton Court.
There is no instinct here, and there shouldn't in those political circles always so eager to ride the first tide of popular feeling that comes their way, to elevate these Olympics to inordinate heights. We can say, though, in no vainglorious way that there is indeed a case that they are the most riveting ever staged, that at the end they nosed ahead of the style and flamenco snap of Barcelona in 1992 and the wonderful swagger of Sydney eight years later.
But then what we do expect from the politicians – and it should still be the demand when the great sports carnival has moved on to Rio in four years – is a duty to truly value and protect the vision inspired by London 2012.
There is, no doubt, less guaranteed reflected glory in the provision of facilities which will enable the most talented and dedicated of young athletes to fulfil their promise down the years than in some heavily financed hot-house preparation for a home Olympics.
That the latter process helped to produce so many startling results, not least in the Velodrome, still ruled so magnificently by Sir Chris Hoy, has made it one powerful catalyst in the success of the Games. But it should not blind us to a part of the motivation, which was the huge potential for self-congratulation for those in power who signed the cheques.
If we have to hope for the best in the long run, and this includes a banishing of the grim assessment of the man who spirited these Olympics from under the noses of Paris, Lord Coe, that this is maybe the first British generation fitter than its children, it shouldn't slacken anyone's appreciation of the triumph that was celebrated here last night.
These were, after all, the Olympics that exceeded all expectations as they headed inevitably and in the end near flawlessly to the formal praise of the Olympic head of state Rogge at the end of last night's closing ceremony.
So why were they such "great" Games? Because they were filled not only with great athletic deeds, of which those of the irrepressible Bolt so often touched the surreal, but also because of their humanity.
They were loved, in the manner of Barcelona and Sydney, from the starting gun. They didn't have the resources of Beijing. They had this fine but essentially functional stadium which will surely be pulled down and built again complete with corporate boxes if it comes into the hands of Tottenham Hotspur, rather than the exquisite Bird's Nest arena thrown up without financial accountability by the Chinese.
They didn't have the spectacular swimming and diving Cube where Phelps won eight golds. They didn't have extraordinary evidence of the ancient art of pyrotechnics financed so hugely in Beijing.
But then nor did they have to bus in schoolchildren and off-duty military to the beach volleyball and hockey and hand out flags to be waved in well-drilled unison. The people embraced London 2012 with a spontaneity that swelled like a great tide. And so did so many visitors, charmed by the beach volleyball at Horse Guards Parade and the equestrianism ridden out against the backcloth of Greenwich Palace. London was a player, too, and surely won a gold medal of its own.
One night an elderly American man, who walked with the aid of a stick, told a crowd coming off the Javelin train at St Pancras that he had been to every Summer Games since Rome in 1960, when Muhammad Ali made his entry into public affairs, and that he believed London to be the best. It was because of the people, he said, because of the excitement that had been so unrestrained – and so inspiring to the greatest and most obscure competitors alike.
You could present so many similar snapshots, you could replay again the extraordinary emotion that came when Farah and Ennis and the long jumper Greg Rutherford won three gold medals in less than an hour. You could try to regenerate the charge of electricity that came when Bolt entered the stadium with a nonchalant jocularity that delighted but did not deceive his rapt audience, and relive the extraordinary exhilaration when Hoy, the knight who some thought was honoured too soon, swept in for his sixth gold. You could do all of that and still find, sensation piled upon sensation, a gallery of heroes and heroines.
There was supposed to be a security crisis but the fear of it did not survive the first collision with an amiable paratrooper. The Bobbies were civil and the buses worked. The volunteers were fastidious and kind.
You thought of all this, you recalled once more the sight of Bolt and the meaning of Mo, and you felt pride that the old town had put on such a show. Then the music died and the flame went out and you wondered if we would feel quite this way ever again.
Comments